The chemistry of phosphorodiselenoates: structure, catalysis and formation of Se-esters

Abstract

Though metal complexes of dialkyl diselenophosphate ligands [Se 2 P(OR) 2 ] À (dsep) have been reported in several occasions, the solid-state structure of isolated dsep ligands is still unknown. Herein the ammonium salt of the dsep ligand, NH 4 Se 2 P(O i Pr) 2 , is structurally characterized and N-HÁ Á ÁSe type of H-bonding interactions are revealed. In addition, the NH 4 Se 2 P(OR) 2 ligands serve as an ammonia source in the Fe powder catalyzed condensation of acetone with ammonia to form 2,2,6,6-tetramethyl-4-oxopiperidinium salts of the dsep ligand, [{H 2 N(CH 2 ) 2 (CMe 2 ) 2 CO}{Se 2 P(OR) 2 }] (1a = i Pr, 1b = Et) of which 1b is structurally characterized. Novel syntheses of Se-esters of O,O 0 -dialkylphosporodiselenoic acid, 2, 3, 4, 5, 6, 7, directly from the ammonium salts have been achieved. The reactions, where one of the Se atoms of the dsep unit acts as the nucleophilic center, include Michael addition, epoxide ring opening addition, acylation and a-alkynation.

Structural studies of phosphor-1,1-diselenoato Mn(I) and Re(I) complexes

“…Unlike a set of satellite is depicted in 2a-b, two 31 P-77 Se coupling constants in the range of 577-610 Hz in 4a-b must have been originated from the coupling by two, non-equivalent 77 Se nuclei in solution. All the 31 P-77 Se coupling constants observed in compounds 1-4 suggest the P-Se bond order remains in between 1 and 2 [21]. The coupling constants observed in 31 P NMR spectra are also comparable with those from 77 Se NMR spectra for these compounds.…”

“…The Mn-Se distances are comparable to that observed in the Mn[Ph 2 P(Se)NP(Se)Ph 2 )] 2 (2.5344(11) and 2.5691(11) Å) [13] and are indicative of their covalent nature [24]. The P-Se lengths [2.186(2) and 2.151(2) Å] are slightly longer than that in isopropyl homolog of ammonium salt of dsep ligand NH 4 Se 2 PðO i PrÞ 2 [2.1414(8) and 2.1249(8) Å] [21]. Intermolecular SeÁ Á ÁSe interactions form 1D network (Fig.…”

Reactivities of Secondary Phosphine Selenides Cp(CO)2FeP(Se)(OR)2: Formation of a Diiodine Charge Transfer Adduct and Se-Methylation

“…11b A similar value of 1 J PSe (480.7 Hz) was observed for the P-Se single bond in the [( i PrO) 2 PSe 2 CH 2 ] 2 CH 2 reported from this group. 15 The coupling of SeCH 3 protons with P ( 3 J PH ) in 2b (11.88 Hz) and 2c (11.94 Hz) in the 1 H NMR spectra also confirms the Se-methylation. It is worth noting that the precursor diselenophosphates [(OR) 2 PSe 2 ]can act as nucleophiles and one of the two Se atoms can be alkylated by the reaction with alkyl halide.…”

“…It is worth noting that the precursor diselenophosphates [(OR) 2 PSe 2 ]can act as nucleophiles and one of the two Se atoms can be alkylated by the reaction with alkyl halide. 15 During the formation of metalloligands 1a-c, the Fp unit gets connected to the diselenophosphate with the loss of one Se atom. The remaining Se atom in each of the metalloligands (1a-c) still retains its nucleophilic character to form a Se-methylated product.…”

Reaction of Vinyl Selenides with Secondary Phosphines and Elemental Selenium: One‐Pot Selective Synthesis of a New Family of Diselenophosphinic Se‐Esters

“…As for the synthesis of diselenophosphinic Se ‐esters and their ‐phosphate or ‐phosphonate congeners , the most conventional method is the reaction between organic halides and the salts of [R 2 PSe 2 ]Cat type (R = organic groups, RO or R 2 N; Cat = metal or ammonium). Alternatively, such Se ‐esters can be assembled by condensation of selenophosphinic chlorides, R 2 P(Se)Cl, with metal alkyl‐ or arylselenolates .…”